The goal of this Phase I project is to prove the feasibility of fabricating a small fiber optic sensor that includes sensing elements for simultaneous measurement of up to three different physical parameters using a single strand of optical fiber, and which can ultimately be produced at reasonable cost. The sensor would be used to measure 1) blood or tissue temperature, 2) blood pressure, and 3) local heat flow, air flow or blood flow for various clinical applications. In this proposal, however, the target application is angioplasty. Since the temperature and flow sensing combination had already been demonstrated in earlier Luxtron studies, this Phase I proposal will concentrate on the combination of temperature and pressure sensing. In Phase II, the proven blood flow measurement capability will be integrated into the system, forming a final sensor which is capable of measuring all three parameters simultaneously. A successful Phase I program will produce prototypes made with a single optical fiber carrying both the temperature and pressure sensing elements. The resulting probe will have a maximum diameter of 1 mm, with potential for further performance capabilities relative to the application of primary interest, namely, angioplasty.